In a signal transmitter and a signal receiver, a multiplexing part multiplexes a video signal and a time-base-compressed audio signal on the basis of a multiplexing control signal to transmit the multiplexed signal through a data line in the signal transmitter. Further, a demultiplexing part demultiplexes a video/audio multiplexed signal received through the data line into the original video signal and audio signal by a demultiplexing control signal in the signal receiver. According to the so-configured signal transmitter and signal receiver, it is possible to realize a signal transmission system compliant with the DVI standard, in which the audio signal as well as the video signal can be transmitted.